Centering prop



W. GNIRS ET AL CENTERING PROP June 14, 1932.

Filed Jan. 29, 1951 Patented June 14, 1932 WILHELM GNIRS AND ADOLF URBAN, OF BASE'L, SWITZERLAND CENTERING PRO]? Application filed January 29, 1931, Serial No. 512,113, and in Switzerland February 4, 1930.

This invention relates to a more rational and convenient propping of concrete ceilings.

Proppings are to-day often carried out with wooden props cut to length, which are forced against the falsework by means of a double wedge. Metal props are also known, which can be adjusted to the required length by screwing or unscrewing a thread or by a winch.

w The novelty of the invention consists, in that a wooden prop is connected to an iron base by means of a sliding shoe and a guide bar. The falsework prop can be adjusted to any desired length within the limits determined by the length of the guide bar in that the slide shoe can be fixed automatically in any position by shifting a wedge. By loosening the wedge the automatic braking can be suppressed. An unintentional loosening of the wedge and therefore of the guide shoe is rendered impossible by the locking device according to the invention.

An embodiment of the invention is illustrated by way of example in the accompanying drawing in which:

Fig. 1 shows the prop in side elevation.

Fig. 2 is a cross section on line 11-11 of Fig. 1.

A wooden prop a is rigidly connected to a slide shoe 6. The slide shoe 6 is guided on a guide bar 0 at the top by a rigid strap cl and at the bottom by means of two links 7 connected the one with the other by means of a bolt e. A fiat ended wedge g is arranged between the guide bar 0 and the strap (Z on the one hand and the bolt 6 on the other hand. The upper end of the wedge is bent over so that, when disengaged, it cannot fall out from between the strap and the guide bar.

The bolt 6 connected to the slide shoe 6 by means of the two links f bears on the wedge surface proper. If the wedge g is tightened on the back of the guide bar 0, the slide shoe 1) will participate in the automatic wedging efi'ect owing to the friction. If the wedge g is loosened, the slide shoe 5 slides ofi. In order to prevent an unintentional loosening of the wedge and therefore of the slide shoe, a locking device 8 is arranged on the strap d. This device consists of a fixable fiat iron, bent over at its upper end which engages under the bent over portion of its wedge. An unintentional loosening of the wedge is prevented by the fixing of the fiat iron. The upper end of the wedge is protected against unintentional contacts by a hinged cap.

The advantage obtained by the invention consists in that mechanical elements such as toothed'wheels and threads, which are undesirable in the building trade, are avoided by the employment of the slide shoe, guide bar and wedge. The falsework prop according to the invention further allows a quick adj ustment, as the slide shoe can be pulled with a single movement over the entire length of the guide bar, after the wedge has been loosened. The easy readjustability resents a very considerable advantage, if tie prop sinks slightly, after being positioned, it can easily be readjusted by alternate blows with a hammer on the wedge and on the slide shoe.

The invention is the practical combination of the most simple mechanical elements, by means of which a rational and convenient tool for the building trade is provided.

We claim 1. A centering prop, comprising in combination an iron base, a guide bar on said base, a wooden prop at the side of said guide bar, a shoe fixed on the lower end of said prop, a rigid strap extending from the upper end of said shoe around said guide bar, two links hingedly mounted at one end one on each side of said shoe extending to beyond the side of said guide bar remote from said prop, a. bolt connecting the other ends of said links, and a wedge between said guide bar and both said rigid strap and said bolt adapted to be held by said strap and to coact with said links and said bolt to automatically clamp said prop in adjusted position on said guide bar.

2. A centering prop as specified in claim 1, comprising in combination with the guide bar the shoe, the rigid strap and the wedge, an outwardly and downwardly bent end on the upper end of said Wedge adapted to resiliently engage between said strap and said guide bar, and a locking device on said strap adapted to prevent the unintentional loosening of said wedge and therefore of said shoe.

In testimony whereof we affix our signatures.

WILHELM GNIRS. ADOLF URBAN. 

